This invention relates to oil processing, more particularly to a composition of a fuel oil, such as heavy fuel oil that may be used in marine power units and boiler plants.
A heavy fuel oil is known which comprises a distillate of asphalt thermal cracking and a deasphalting residue in the ratio from 30:70 to 50:50 (SU 1575560, C 10 L 1/04, 1999).
However, this fuel may be unstable and does not possess required viscosity-temperature properties.
Another type of available fuel is a heavy fuel oil that comprises a viscosity breaking residue of heavy oil fractions and deasphalted heavy oil fractions in the ratio from 70:30 to 90:10. In some instances, this fuel may contain light oil fractions as described in JP 60-123554, C 08 L 91/00, 1985.
In Russia, however, deasphalted oil fractions are mainly used as raw stock in production of lubricants, and their availability is limited.
Another known heavy fuel oil is based on the viscosity breaking residue of a black oil and tar mixture having the boiling temperature range from 360° C.-KK and comprises 1-5% by wt. of an extract from the process of selective extraction of gas oil, up to 10% by wt. of heavy catalytic cracking gas oil, up to 2% by wt. of a residual component obtained from the process of deasphalting oils with propane, and 0.5-2.5% by wt. of slop wax (RU 2185415, C 10 L 1/04, 2002).
A disadvantage of the said technical solution is that the use of a residual component obtained in the process of oils deasphalting with propane in its composition leads to a significant increase in viscosity and a higher pour point of the fuel.